10 Terrible Diseases You Could Have Without Even Knowing

We’ve all been there — you wake up in the morning to discover your throat feels scratchy, your head is pounding, and your temperature has risen. These common symptoms indicate the flu has held your body hostage. Whether you go to the doctor for a proper diagnosis or not, you know full well you need to cancel your plans and stay in bed to get over this viral infection.

It may be easy to spot the flu from a mile away, but not every disease is as easy to detect. Here are 10 that could be wreaking havoc on your body without you even knowing it.

1. Chlamydia

Chlamydia is one of the most common STDs in the U.S. | iStock.com

This is one of the most common STDs in the U.S., yet many people who have it don’t know due to its lack of symptoms. This infection can cause lasting damage to a woman’s fallopian tubes, which can eventually lead to infertility or an increased risk of an ectopic pregnancy, says MedicineNet. This infection can live in the cervix, urethra, vagina, rectum, or throat, and it can also be passed from mother to child during birth. If you’re sexually active, it’s important to get tested just in case you have this (or any) STD.

2. Diabetes

You can have diabetes and not even know. | iStock.com

It’s possible to be born with type 1 diabetes, but developing type 2 is also common as you age. The American Diabetes Association explains the condition causes blood glucose levels to rise abnormally high because your body fails to properly use the hormone insulin, which helps to regulate your blood sugar. Those who have diabetes often report feeling very thirsty, feeling an increase in appetite, and feeling tired. Unfortunately, many people can come up with any number of excuses for feeling hungry, thirsty, or tired, so this makes the disease difficult to detect early on. And for women who develop gestational diabetes, there are often no symptoms at all.

3. Glaucoma

Unfortunately, glaucoma is the second leading cause of blindness in the U.S., and it comes with few to no symptoms, John Berdahl, M.D., writes for All About Vision. All eye disorders associated with glaucoma damage the optic nerve, which is responsible for carrying information from the eye to the brain. Usually, those who have this disease also experience pressure behind the eyes, but this doesn’t always happen. When the disease advances, it can lead to loss of peripheral vision or total blindness.

4. Gonorrhea

Gonorrhea is a very common STD. | iStock.com

According to the Centers for Disease Control and Prevention, gonorrhea is another common STD without symptoms. Men may experience burning during urination, discharge from the penis, and painful or swollen testicles if they have gonorrhea. There’s a chance women may experience painful urination and vaginal bleeding between periods, but this can easily be mistaken for a bladder infection and doesn’t typically lead many women to getting tested. As with all STDs, condoms can greatly reduce your risk. It’s important to get tested regularly if you’re sexually active.

5. Celiac disease

Celiac disease often comes with no symptoms. | iStock.com

Even though more people than ever are avoiding gluten for fear of its ill effects on the body, many people with celiac disease don’t know they have it. According to the Celiac Disease Foundation, it’s an autoimmune disorder where eating gluten, a protein found in rye, wheat, or barley, causes damage to the small intestine. Adults with this disease often experience iron deficiency, fatigue, joint pain, depression, migraines, and vitamin deficiency. While it may seem like it’d be easy to notice if gluten isn’t agreeing with you, the Foundation notes there are more than 200 symptoms possible, and no two cases look alike.

6. Osteoporosis

This disease literally means “porous bones.” | iStock.com

The National Osteoporosis Foundation says this disease is responsible for over 2 million broken bones per year. Essentially, those with osteoporosis have weak bones due to bone density loss. Some people even lose height and posture if it affects their vertebrae. Still, it can take many years for those with osteoporosis to notice any difference in their bones, and many people only realize something is amiss after a fracture. There are no clear signs or symptoms to watch out for, though most older adults should be sure to get plenty of calcium and vitamin D.

7. Huntington’s disease

Huntington’s disease is incurable. | iStock.com

This insidious disease is a genetic disorder that you can have all the way through your adolescence without ever knowing it. Huntington’s disease causes the nerves in your brain to break down, and is rare but fatal, explains the Huntington’s Disease Society of America. The symptoms are typically described as being a cross between ALS, Parkinson’s, and Alzheimer’s because of the way your physical body and mental strength are compromised. You may start to notice symptoms between the ages of 30 and 50, but it’s a tough one to detect.

8. Colon cancer

Colon cancer often has no signs or symptoms. | iStock.com

Though self-checking for breast cancer is becoming increasingly popular and knowing how to detect skin cancer is now the norm, colon cancer might just be the sneakiest iteration of them all — and one of the deadliest. According to Mayo Clinic, colon cancer starts in the large intestine as small, noncancerous polyps that eventually grow to become cancer. Once the cancer has existed past the beginning stages, it’s common to experience either diarrhea or constipation more consistently, and you may find blood in your stool accompanied with weight loss and fatigue. Though colon cancer is one of the most treatable cancers in its early stages, many people who skip their cancer screenings do not know they have it and end up living with the cancer for years.

9. Deep vein thrombosis

According to MedlinePlus, deep vein thrombosis is a blood clot that forms in a vein deep in the body, often in the lower leg or thigh, and you may not even realize it’s happening. If the clot breaks loose and travels up your bloodstream to your lungs, this can cause low oxygen levels in your blood, serious lung damage, or death in extreme cases. The National Heart, Lung, and Blood Institute says only about half of those with DVT experience symptoms, which can include warmth and tenderness over certain veins, redness, or pain and swelling in the affected area. A doctor can offer tests to check if you are experiencing any clotting in your blood, but it’s also important to regularly move around to lower your risk.

10. Hepatitis C

Hepatitis C can cause a range of problems with the liver. | iStock.com

This virus attacks your liver, and the effects can be mild or severe depending on how long it goes untreated. The World Health Organizations says hepatitis C is commonly spread through sharing injection equipment for drug usage, but it can also be spread through sexual contact. While some people only have an acute infection that clears itself with no medical treatment within six months, it can become chronic and lead to liver damage later on. There’s about a two-week window from the time you contract the disease to the time any symptoms will show. However, roughly 80% of cases don’t exhibit symptoms. In order to minimize your risk, limit sexual partners and always practice good hygiene.